CSIR Mk1 & CSIRAC, Trevor Pearcey & Geoff Hill, Australia, 1951

Trevor Pearcey at the CSIR Mk1
Trevor Pearcey at the CSIR Mk1

CSIRAC was an early digital computer designed by the British engineer Trevor Pearcey as part of a research project at CSIRO ( Sydney-based Radiophysics Laboratory of the Council for Scientific and Industrial Research)  in the early 1950’s. CSIRAC was intended as a prototype for a much larger machine use and therefore included a number of innovative ‘experimental’ features such as video and audio feedback designed to allow the operator to test and monitor the machine while it was running. As well as several optical screens,  CSIR Mk1 had a built-in Rola 5C  speaker mounted on the console frame. The speaker was an output device used to alert the programmer that a particular event had been reached in the program; commonly used for warnings, often to signify the end of the program and sometimes as a debugging aid. The output to the speaker was basic raw data from the computer’s bus and consisted of an audible click. To create a more musical tone, multiple clicks were combined using a short loop of instructions; the timing of the loop giving a change in frequency and therefore an audible change in pitch.

A closeup of the CSIRAC console switch panel. Note the multiple rows of 20 switches used to set bits in various registers.
The CSIRAC console switch panel with multiple rows of 20 switches used to set bits in various registers.

The first piece of digital computer music was created by Geoff Hill and Trevor Pearcey on the  CSIR Mk1 in 1951 as a way of testing the machine rather than a musical exercise. The music consisted of excerpt from  popular songs of the day; ‘Colonel Bogey’, ‘Bonnie Banks’, ‘Girl with Flaxen Hair’ and so on. The work was perceived as a fairly insignificant technical test and wasn’t recorded or widely reported:

An audio reconstruction  of CSIRAC playing Colonel Bogey (c.1951)
 CSIRAC plays In Cellar Cool with a simulation of CSIRAC’s room noises.

CSIRAC – the University’s giant electronic brain – has LEARNED TO SING!

…it hums, in bathroom style, the lively ditty, Lucy Long. CSIRAC’s song is the result of several days’ mathematical and musical gymnastics by Professor T. M. Cherry. In his spare time Professor Cherry conceived a complicated punched-paper programme for the computer, enabling it to hum sweet melodies through its speaker… A bigger computer, Professor Cherry says, could be programmed in sound-pulse patterns to speak with a human voice…
The Melbourne Age, Wednesday 27th July 1960

Later version of the CSIRAC at The University of Melbourne
Later version of the CSIRAC at The University of Melbourne

…When CSIRAC began sporting its musical gifts, we jumped on his first intellectual flaw. When he played “Gaudeamus Igitur,” the university anthem, it sounded like a refrigerator defrosting in tune. But then, as Professor Cherry said yesterday, “This machine plays better music than a Wurlitzer can calculate a mathematical problem”…
Melbourne Herald, Friday 15th June 1956:

Portable computer: CSIRAC on the move to Melbourne, June 1955
Portable computer: CSIRAC on the move to Melbourne, June 1955

The CSIR Mk1 was dismantled in 1955 and moved to The University of Melbourne, where it was renamed CSIRAC. Professor of Mathematics, Thomas Cherry, had a great interest in programming and music and he created music with CSIRAC. During it’s time in Melbourne the practice of music programming on the CSIRAC was refined allowing the input of music notation. The program tapes for a couple of test scales still exist, along with the popular melodies ‘So early in the Morning’ and ‘In Cellar Cool’.

Music instructions for the CSIRAC by Thomas Cherry
Music instructions for the CSIRAC by Thomas Cherry
Music instructions for the CSIRAC by Thomas Cherry
Music instructions for the CSIRAC by Thomas Cherry

Later version of the CSIRAC at The University of Melbourne
Later version of the CSIRAC at The University of Melbourne



Australia’s First Computer Music, Common Ground Publishing, Paul Doornbusch pauld@koncon.nl


The ‘Free Music Machine’. Percy Grainger & Burnett Cross, USA/Australia , 1948

The Free Music Machine (1948) or "The Electric Eye Tone Tool Cross-Grainger for Playing Graingers Free Music"
The Free Music Machine (1948) or “The Electric Eye Tone Tool Cross-Grainger for Playing Grainger’s Free Music”
The ‘Free Music Machine’ was created by musician and singer Burnett Cross and the Australian composer Percy Grainger. Grainger a virtuoso Pianist and pupil of Bussoni, had been developing his idea of “free music” since 1900: based on eighth tones and complete rhythmic freedom and unconventionally notated on graph paper. Grainger had experimented using collections of Theremins and changing speeds of recorded sounds on phonograph disks and eventually developed his own instruments. Graingers experiments with random music composition pre-dated those of John Cage by 30 years with “Random Round” written in the 1920’s. Graingers first experiments used a Pianola “player piano” controlling three Solovoxes by means of strings attached to the Pianola’s keys, this combination was abandoned as it was not possible to create a continuous glissando effect from the Pianola. Grainger started work on a more elaborate but eccentric machine in collaboration with Burnett Cross and his wife, Ella Grainger. The Free Music Machine was a machine that controlled the pitch, volume and timbre of eight oscillators.Two large rollers fed four sets of paper rolls over a set of mechanical arms that rolled over the cut contours of the paper and controlled the various aspects of the oscillators.
The Kangaroo Poutch Free Music Machine (Grainger's diagram)
The Kangaroo Poutch Free Music Machine (Grainger’s diagram)
Graingers notes describing the above diagram, April 1952:
” 8 oscillators, able to play the gliding tones and irregular (beatless) rythms of Graingers FREE MUSIC (first thought of around 1892), are manipulated by paper graphs, towered discs and metal arms.A sheet of light brown wrapping paper 80 inches high (called “main paper”), is rolled continually from the “Feeder” revolving turret into the “Eater” revolving turret, passing through a metal cage on its way (the cage keeps the Main Paper, the graphs and ths discs in place). Each of the 8 oscillators has its own special pitch control graph and sound strength control graph. To the front of the main paper are attached 4 pitch-control graphs (mauve and greenish paper) and 4 tone-strength control graphs (pinkish paper), their top edges cut into “hills and dales” in accordance with the intervals & tone strength desired. These graphs operate oscillators 1,2,3,4. To the back of the Main Paper are attached 4 additional pitch control graphs & 4 additional tone strength control graphs, operating oscillators 5,6,7,8 The bottoms of these 16 graphs are sewn onto the main paper at various heights but the top of each graph is left unattached. Into each pouch thus formed (between the main paper and thegraph paper) is inserted a towered metal disc, the tower riding the upon the top edge of the graph & following its up and down movements. These movements are passed on to the axle and tone strength control box of each oscillator by means of metal arms, causing whatever changes in pitch and volume are intended. The blue-and-white discs controlling tone strengths are smaller than the variously coloured discs controlling pitch. In the above sketches the connecting electric wires are not shown.”
DCP_00figure 2. Detail view of one of the valve oscillators (photo R.Linz)
Grainger specified the requirements of his Free Music Machine to be:

  • To play any pitch of any size, half, quarter or eighth tones, within the range of 7 voices.
  • To be able to pass from pitch to pitch by way of a controlled guide as well as by leap
  • Complex irregular rhythms must be able to be performed past the scope of human execution. Dynamics were to be precisely controlled.
  • The machine had to be to be run and maintained by the composer.

Grainger was a continual experimenter picking up skills where necessary, amongst some of the eccentric instruments he produced were:

  • The first sliding pipes for playing gliding tones.
  • The electrical reproducing Duo Art grand piano 1932, for beat-less music and irregular barring.
  • The portable folding harmonium.
  • The Burnett Cross movie-film gliding soundtrack, (abandoned as it did not allow Grainger to deal directly with the sounds themselves)
  • The Smith’s Organ Flute Pipe, set up with hanging mops, rolling pins.
  • A range of experiments with reeds in boxes used as tone tools played with vacuum cleaners (1944-6)
  • The sewing machine and hand drill (to act as an oscillator for playing variable tones) October 1951.
  • The “Kangaroo Pouch”, Grainger’s own efficient framework design with the skatewheel mountings suggested by his collaborator, Burnett Cross and four vacuum-tube oscillators built by Branch, an electronics student, from the local White Plains High School.
  • The Butterfly Piano conversion tuned in 6th tones, (1952)
  • The electric eye tone tool Cross-Grainger 1957-59, the last remaining component.
percy grainger_Free Music Tone-Tool Machine
Percy Grainger’s description of Free Music. December 6th, 1938
FREE MUSIC (Tablet 2)

“Music is an art not yet grown up; its condition is comparable to that stage of Egyptian bas-reliefs when the head and legs were shown in profile while the torso appeared – the stage of development in which the myriad irregular suggestions of nature can only be taken up in regularised or conventionalised forms. With Free Music we enter the phase of technical maturity such as that enjoyed by the Greek sculptors when all aspects and attitudes of the human body could be shown in arrested movement.Existing conventional music (whether “classical” or popular) is tied down by set scales, a tyrannical (whether metrical or irregular) rhythmic pulse that holds the whole tonal fabric in a vice-like grasp and a set of harmonic procedures (whether key-bound or atonal) that are merely habits, and certainly do not deserve to be called laws. Many composers have loosened, here and there, the cords that tie music down. Cyril Scott and Duke Ellington indulge in sliding tones; Arthur and others use intervals closer than the half tone; Cyril Scott (following my lead) writes very irregular rhythms that have been echoed, on the European continent, by Stravinsky, and others; Schoenberg has liberated us from the tyranny of conventional harmony. But no non-Australian composer has been willing to combine all these innovations into a consistent whole that can be called Free Music.It seems to me absurd to live in an age of flying and yet not to be able to execute tonal glides and curves – just as absurd as it would be to have to paint a portrait in little squares (as in the case of mosaic) and not to be able to use every type of curved lines. If, in the theatre, several actors (on the stage together) had to continually move in a set theatrical relation to each other (to be incapable of individualistic, independent movement) we would think it ridiculous, yet this absurd goose-stepping still persists in music. Out in nature we hear all kinds of lovely and touching “free” (non-harmonic) combinations of tones, yet we are unable to take up these beauties and expressivenesses into the art of music because of our archaic notions of harmony.Personally I have heard free music in my head since I was a boy of 11 or 12 in Auburn, Melbourne. It is my only important contribution to music. My impression is that this world of tonal freedom was suggested to me by wave movements in the sun that I first observed as a young child at Brighton, Vic., and Albert Park, Melbourne. (See case I)

Yet the matter of Free Music is hardly a personal one. If I do not write it someone else certainly will, for it is the goal that all music is clearly heading for now and has been heading for through the centuries. It seems to me the only music logically suitable to a scientific age.

The first time an example of my Free Music was performed on man-played instruments was when Percy Code conducted it (most skilfully and sympathetically) at one of my Melbourne broadcast lectures for the Australian Broadcasting Commission, in January, 1935. But Free Music demands a non-human performance. Like most true music, it is an emotional, not a cerebral, product and should pass direct from the imagination of the composer to the ear of the listener by way of delicately controlled musical machines. Too long has music been subject to the limitations of the human hand, and subject to the interfering interpretation of a middle-man: the performer. A composer wants to speak to his public direct. Machines (if properly constructed and properly written for) are capable of niceties of emotional expression impossible to a human performer. That is why I write my Free Music for theramins – the most perfect tonal instruments I know. In the original scores (here photographed) each voice (both on the pitch-staves and on the sound- strength staves) is written in its own specially coloured ink, so that the voices are easily distinguishable, one from the other.

Percy Aldridge Grainger, Dec.6, 1938″

percy grainger_Facing PercyJB


The Free Music Machines of Percy Grainger. Rainer Linz